<!DOCTYPE html>
<html>
<head>
    <title>Increment/Decrement Example 1</title>
    <script type="text/javascript">
          
        var age = 29;
        var anotherAge = --age + 2;
        
        alert(age);         //outputs 28
        alert(anotherAge);  //outputs 30

    </script>

</head>
<body>
  
</body>
</html>